Starting issue

[BigJohn]

Check Battery Cables?

[shawn8492]

Mine did this and I bypassed the vats system. I went to breakfast and came out and ir woupdnt start. Everything else worked. Has not done it since the vats bypass so I hope that was the problem.

Sent from my SM-G930V using ZR-1 Net Registry mobile app

[JMO343]

I just took my out to vacuum. It ran for about 10 mins in the the driveway. Go back to try and start it. No luck. Starter solinoid???

John

[JMO343]

Sorry car.!!

[GOLDCYLON]

Originally Posted by geezer

60 / 80 AMP RELAY SPDT SINGLE POLE DOUBLE THROW

Check this item out in Dynomites 'Solutions' at the top of Tech .forums!! Electical Ground Connections And 'Installing Starter Relay'. From experience this will solve your Issue!!!!!

Installed under ECM and in slot between brake booster and fire wall (perfect place for location of Relay).

Wiring modified a bit to assure Pin #87a is not hot at any time.
Pin #30: Purple wire to starter (use 3/8 inch connector on relay).
Pin #87: Red wire battery positive 12v use 3/8 inch connector on relay
(Same gauge wire as purple wire connected to battery positive multiple connection post).
Pin #86: Battery ground (1/4 inch connector on relay connected to ground where battery 12 gauge wire grounded).
Pin #85: Purple wire from clutch switch in wire bundle under ECM use 1/4 inch connector on relay (Red wire on early 1990 ZR-1).
Pin #87a: Not hot at any time and not used.


Insert a short 1/2 inch long section of plastic hose
over the center connector on the Relay which is NOT
used in this application.

Normally this is the solution. My 91 was done by the previous owner because he was stuck several times. Once the car cooled down it will start again. This solves that problem.

[Paul Workman]

Woah! My I say that ALL of the suggestions so far are all valid - far as they go. But, what is lacking is a methodical, logical progression to isolate the problem so that it can be dealt with properly.

Good troubleshooting begins with: KNOWING HOW THE SYSTEM WORKS

If this were my issue (and it has been a couple times over the last 11 years) I'd want to have a roadmap and be able to go step by step. And, maybe the best way to do that is to have a schematic. HOWEVER, it would help to know WHAT YEAR ZR-1 we're dealing with here; a 90-92 or a 93-95 MY?

OVERVIEW:

Before the battery is connected to the starter windings, FIRST there are 3 SWITCHES that must be satisfied (turned ON).

In the case of the 90-92 cars, the starter current first passes through a STARTER ENABLE RELAY (controlled by the CENTRAL CONTROL MODULE [think VATS]), then second through the CLUTCH START SWITCH, and then to the starter solenoid. Within the solenoid housing is a third HEAVY CURRENT switch, activated by the first two switches. This last switch HIGH CURRENT switch connects the battery directly to the starter windings and supplies the HIGH CURRENT power needed to spin the motor.

The "Achilles heal" is the CLUTCH SAFETY SWITCH in the 90-92 cars carries the relatively high current drawn by the starter's solenoid. This high current load results in arching between the contact points within the switch*. The points are eroded by the heat generated by the arching until they begin to fail intermittently at first, but failures increase until the failure becomes total.

NOTE: One can reduce the arching in the CLUTCH SAFETY SWITCH significantly by FIRST pushing the clutch peddle to the floor BEFORE turning the ignition switch to START.

The 93-95 MY cars starter circuits differ slightly in order to eliminate issues stemming from the high current in the 90-92 CLUTCH SAFETY SWITCH.

Instead, the CLUTCH SAFETY SWITCH current is routed to a separate ENABLE relay controlled by the CENTRAL CONTROL [VATS] MODULE). Because the current through this (beefed up) ENABLE relay is very much lower than that in the 90-92 cars, the issue with arching is greatly diminished and thus the "NO START" dilemma is significantly reduced!

Modification for the 90-92 MY Zs

*By installing a auxiliary relay (modification - see "Solutions" sticky) - the current through the CLUTCH SAFETY RELAY can be significantly reduced and start reliability greatly increased.

ALL THAT SAID, none of the (above) means squat to the starter. How the current gets to the starter solenoid switch doesn't change the erosive effect arching will have on those contacts! Sooner or later, the contacts will need to be serviced.

The MEAN TIME BETWEEN FAILUREs for the contacts is measured in the number of switching cycles, NOT mileage. (In my case, the contacts had to be replaced at about 37-40k miles.

Your mileage may vary! But, it is prudent to inspect and R&R whenever taking delivery of an older car, and like changing all the fluids, inspecting/replacing the starter solenoid contacts should be on the list!

The schematic on the left is for the 90-92 MY and the one on the right is for the 93-95 MY ZR-1s.

.

[JMO343]

I will check the security light. If I have to change the starter does anyone know of good Corvette shop close to Long Island that can do this work?


John

[zrfast1]

Just my .02 but I had the same issues you have and drove me nuts. My starter was rebuilt, so I know it wasn't it. Clutch bypass wasn't bypassed so I did it. No joy. Long story short....cleaned the battery cable connections...never had an issue again!!

[JMO343]

I have not done the starter yet and battery is new. How hard is it to replace the starter?


John

[zrfast1]

Starter is located under the coil packs which are under the plenum in the valley of the engine. Take a wire brush to the cable of the connection to the battery first and make sure the cables are very snug, wiggle the cables while tightening..do not over torque! Also do the clutch bypass.....its very easy before you tear into the plenum. Just my .02